using System;

​

public class Program

{

    public static void Main()

    {

​

    }

    public interface IAccount

    {

        void Deposit(decimal amount);

        decimal CheckBalance();

        void Withdraw(decimal amount);

    }

    public class Account : IAccount

    {

        decimal balance;

        public void Deposit (decimal amount)

        {

            balance += amount;

        }

        public decimal CheckBalance()

        {

            return balance;

        }

        public void Withdraw(decimal amount)

        {

            if (balance >= amount)

                balance-=amount;

        }

    }

​

}